Magnetometer with a light emitting diode

ABSTRACT

A device includes a diamond with one or more nitrogen vacancies, a light emitting diode configured to emit light that travels through the diamond, and a photo sensor configured to sense the light. The device also includes a processor operatively coupled to the photo sensor. The processor is configured to determine, based on the light sensed by the photo sensor, a magnetic field applied to the diamond.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to co-pending U.S. application Ser. No. 15/003,281, filed Jan. 21, 2016, titled “MAGNETOMETER WITH LIGHT PIPE,” U.S. application Ser. No. 15/003,298, filed Jan. 21, 2016, titled “DIAMOND NITROGEN VACANCY SENSOR WITH COMMON RF AND MAGNETIC FIELDS GENERATOR,” U.S. application Ser. No. 15/003,309, filed Jan. 21, 2016, titled “DIAMOND NITROGEN VACANCY SENSOR WITH DUAL RF SOURCES,” which issued as U.S. Pat. No. 9,551,763 on Jan. 24, 2017, U.S. application Ser. No. 15/003,062, filed Jan. 21, 2016, titled “IMPROVED LIGHT COLLECTION FROM DNV SENSORS,” each of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates, in general, to nitrogen vacancy centers in diamonds. More particularly, the present disclosure relates to using LEDs to excite nitrogen vacancy centers in diamonds.

BACKGROUND

The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art. Some diamonds have defects in the crystal structure that contain nitrogen. A light source can be used to excite the defect. However, many such light sources are large, bulky, expensive, and/or consume relatively large amounts of power.

SUMMARY

An illustrative device includes a diamond with one or more nitrogen vacancies and a light emitting diode configured to emit light toward the diamond. The device may also include a first photo sensor configured to sense a first portion of the light emitted by the light emitting diode. The first portion of the light may not travel through the diamond. The device may further include a second photo sensor configured to sense a second portion of the light emitted by the light emitting diode. The second portion of the light may travel through the diamond. The device may also include a processor operatively coupled to the first photo sensor and a second photo sensor. The processor may be configured to compare a first signal received from the first photo sensor with a second signal received from the second photo sensor and determine, based on the comparison of the first signal and the second signal, a strength of a magnetic field applied to the diamond.

An illustrative method includes providing power to a light emitting diode. The light emitting diode may be configured to emit light toward a diamond. The diamond may comprise a nitrogen vacancy. The method may also include receiving, at a processor, a first signal from a first sensor. The first signal may indicate a strength of a frequency of a first portion of the light emitted by the light emitting diode. The first portion of the light may not travel through the diamond. The method may also include receiving, at the processor, a second signal from a second sensor. The second signal may indicate a strength of a frequency of a second portion of the light. The second portion of the light may travel through the diamond. The method may further include comparing, based on the first signal and the second signal, the strength of the frequency of the first portion of the light and the strength of the frequency of the second portion of the light to determine a strength of a magnetic field applied to the diamond.

An illustrative method includes emitting, from a light emitting diode, a first light portion and a second light portion, sensing, at a first sensor, the first light portion, and sensing, at a second sensor, the second light portion, wherein the second light portion traveled through a diamond with a nitrogen vacancy. The method may also include comparing the first light portion to the second light portion to determine a strength of a magnetic field applied to the diamond.

An illustrative method includes emitting light from a light emitting diode. The light travels through a diamond with a nitrogen vacancy. The method may further include determining, based on a signal from a photo sensor that sensed the light, a magnetic field applied to the diamond.

An illustrative method includes emitting light from a light source. The light may not be polarized. The light may travel through a diamond with nitrogen vacancies. The method may further include determining, based on a signal from a photo sensor that sensed the light, a magnetic field applied to the diamond.

An illustrative device includes a diamond with one or more nitrogen vacancies, a light emitting diode configured to emit light that travels through the diamond, and a photo sensor configured to sense the light. The device may also include a processor operatively coupled to the photo sensor. The processor may be configured to determine, based on the light sensed by the photo sensor, a magnetic field applied to the diamond.

An illustrative device includes a diamond with one or more nitrogen vacancies, a light source configured to emit light that travels through the diamond. The light may not be polarized. The device may further include a photo sensor configured to sense the light and a processor operatively coupled to the photo sensor. The processor may be configured to determine, based on the light sensed by the photo sensor, a magnetic field applied to the diamond.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the following drawings and the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a magnetometer in accordance with an illustrative embodiment.

FIG. 2 is an exploded view of a magnetometer in accordance with an illustrative embodiment.

FIG. 3 is a block diagram of a computing device in accordance with an illustrative embodiment.

FIG. 4 is a flow diagram of a method for detecting a magnetic field in accordance with an illustrative embodiment.

FIG. 5 is a block diagram of a light emitting diode including a heat sink in accordance with an illustrative embodiment.

FIG. 6 is a block diagram of a battery providing power to a light emitting diode and/or a processor in accordance with an illustrative embodiment.

FIG. 7 is a block diagram of a diamond assembly including a three-dimensional Helmholtz coil in accordance with an illustrative embodiment.

The foregoing and other features of the present disclosure will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

Nitrogen-vacancy centers (NV centers) are defects in a diamond's crystal structure, which can purposefully be manufactured in synthetic diamonds. In general, when excited by green light and/or microwave radiation, the NV centers cause the diamond to generate red light. When an excited NV center diamond is exposed to an external magnetic field the frequency of the microwave radiation at which the diamond generates red light and the intensity of the light change. By measuring this change and comparing it to the microwave frequency that the diamond generates red light at when not in the presence of the external magnetic field, the NV centers can be used to accurately detect the magnetic field strength.

In many instances, a light source is used to provide light to the diamond. The more light that is transmitted through the diamond, the more light can be detected and analyzed to determine the amount of red light emitted from the diamond. The amount of red light can be used to determine the strength of the magnetic field applied to the diamond. Accordingly, in some instances, lasers are used to provide light to the diamond. Lasers can provide concentrated light to the diamond and can focus the beam of light relatively easily.

However, lasers may not be the most effective light source for all applications. For example, some lasers produce polarized light. Because the axes of the NV centers may not all be oriented in the same direction, the polarized light from a laser may excite NV centers with axes oriented in one direction more effectively than NV centers with axes oriented in other directions. In instances in which sensitivity in all directions (or more than one direction) is desired, non-polarized light may be used. The non-polarized light may affect the NV centers of different orientations (more) uniformly. In such instances, a light source such as a light-emitting diode (LED) may be used as the light source. In some instances, lasers that produce non-polarized light may be used. For example, helium-neon (HeNe) lasers can be used.

In some instances, lasers are relatively bulky and large compared to LEDs. In such instances, using LEDs as the light source for a magnetometer using a diamond with NV centers may provide a more compact and versatile sensor. In some instances, lasers user more power to produce light than do LEDs. In such instances, LEDs may allow a power source, such as a battery 500 (see FIG. 6), to last longer, be smaller, and/or provide less power.

FIG. 1 is a block diagram of a magnetometer in accordance with an illustrative embodiment. An illustrative magnetometer 100 includes an LED 105, source light 110, a diamond 115, red light 120, a filter 125, filtered light 130, a photo detector 135, and a radio frequency transmitter 145. In alternative embodiments, additional, fewer, and/or different elements may be used.

The LED 105 can be used to produce the source light 110. In alternative embodiments, any suitable light source can be used to produce the source light 110. For example, a light source that produces non-polarized light can be used. In embodiments in which an LED is used, any suitable LED may be used. For example, the LED 105 can emit primarily green light, primarily blue light, or any other suitable light with a wavelength shorter than red light.

In some embodiments, the LED 105 emits any suitable light, such as white light. The light can pass through one or more filters before entering the diamond 115. The filters can filter out light that is not the desired wavelength.

The source light 110 is emitted by the LED 105. The source light 110 can be any suitable light. In an illustrative embodiment, the source light 110 has a wavelength of between 500 nanometers (nm) and 600 nm. For example, the source light 110 can have a wavelength of 532 nm (e.g., green light), 550 nm, or 518 nm. In some embodiments, the source light 110 can be blue (e.g., with a wavelength as low as 450 nm). In yet other embodiments, the source light 110 can have a wavelength lower than 450 nm. In some embodiments, the source light 110 can be any color of visible light other than red.

An illustrative diamond 115 includes one or more nitrogen vacancy centers (NV centers). As explained above, each of the NV centers' axes can be oriented in one of multiple directions. In an illustrative embodiment, each of the NV centers are oriented in one of four directions. In some embodiments, the distribution of NV centers with any particular axis direction is even throughout the diamond 115. The diamond 115 can be any suitable size. In some embodiments, the diamond 115 is sized such that the source light 110 provides a relatively high light density. That is, the diamond 115 can be sized such that all or almost all of the NV centers are excited by the source light 110. In some instances, the LED 105 emits less light than a laser. In such instances, a thinner diamond can be used with the LED 105 to ensure that all or nearly all of the NV centers are excited. The diamond can be “thinner” in the direction that the source light 110 travels. Thus, the source light 110 travels a shorter distance through the diamond 115.

A magnet 140 can be used to provide a magnetic field. When the magnetic field is applied to the diamond 115 and light is traveling through the diamond 115, the NV centers can cause the amount of red light emitted from the diamond 115 to be changed. For example, when the source light 110 is pure green light and there is no magnetic field applied to the diamond 115, then the red light 120, which is emitted from the diamond 115, is used as a baseline level of red light 120. When there is a magnetic field applied to the diamond 115, such as via the magnet 140, the amount of red light 120 varies in intensity. Thus, by monitoring the amount of red light from a baseline (e.g., no magnetic field applied to the diamond 115) in the red light 120, a magnetic field applied to the diamond 115 can be measured. In some instances, the red light 120 emitted from the diamond 115 can be any suitable wavelength.

The radio frequency transmitter 145 can be used to transmit radio waves to the diamond 115. The amount of red light emitted from the diamond 115 changes based on the frequency of the radio waves absorbed by the diamond 115. Thus, by modulating the frequency of the radio waves emitted from the radio frequency transmitter 145 the amount of red light sensed by the photo detector 135 may change. By monitoring the amount of red light sensed by the photo detector 135 relative to the frequency of the radio waves emitted by the radio frequency transmitter 145, the strength of the magnetic field applied to the diamond 115 by the magnet 140 can be determined.

In an illustrative embodiment, a photo detector 135 is used to receive the light emitted from the diamond 115. The photo detector 135 can be any suitable sensor configured to analyze light emitted from the diamond 115. For example, the photo detector 135 can be used to determine the amount of red light in the red light 120.

As illustrated in FIG. 1, some embodiments include a filter 125. The filter 125 can be configured to filter the red light 120. For example, the filter 125 can be a red filter that permits red light to pass through the filter 125 but blocks some or all of non-red light from passing through the filter 125. In alternative embodiments, any suitable filter 125 can be used. In some embodiments, the filter 125 is not used. In embodiments that include the filter 125, the red light 120 emitted from the diamond 115 passes through the filter 125, and the filtered light 130 (which is emitted from the filter 125) travels to the photo detector 135. In embodiments in which a filter 125 is used, greater sensitivity may be achieved because the photo detector 135 detects only the light of interest (e.g., red light) and other light (e.g., green light, blue light, etc.) does not affect the sensitivity of the photo detector 135.

FIG. 2 is an exploded view of a magnetometer in accordance with an illustrative embodiment. An illustrative magnetometer 200 includes an LED 205, a housing 210, a source light photo sensor 215, a mirror tube assembly 220, electromagnetic glass 225, a concentrator 230, retaining rings 235, a diamond assembly 240, a concentrator 245, a modulated light photo sensor 250, a sensor plate 255, and a lens tube coupler 260. In alternative embodiments, additional, fewer, and/or different elements may be used. Additionally, the embodiment illustrated in FIG. 2 is meant to be illustrative only and not meant to be limiting with respect to the orientation, size, or location of elements.

An illustrative LED 205 includes a heat sink 206 (see FIG. 5) that is configured to dissipate into the environment heat created by the LED 205. In the embodiment illustrated in FIG. 2, at least a portion of the LED 205 (e.g., a cylindrical portion) fits within the housing 210. Adjacent to the LED 205 within the housing 210 is the mirror tube assembly 220. The mirror tube assembly 220 is configured to focus the light from the LED 205 into a concentrated beam.

The source light photo sensor 215 is configured to receive a portion of the light emitted from the LED 205. In some embodiments, the source light photo sensor 215 can include a green filter. In such embodiments, the source light photo sensor 215 receives mostly or all green light. In embodiments in which the source light photo sensor 215 is used, the amount of green light sensed by the source light photo sensor 215 can be compared to the amount of red light sensed by the modulated photo sensor 250 to determine the magnitude of the magnetic field applied to the diamond assembly 240. As discussed above, in some embodiments, the source light photo sensor 215 may not be used. In such embodiments, the amount of red light sensed by the modulated photo sensor 250 can be compared to a baseline amount of red light to determine the magnitude of the magnetic field applied to the diamond assembly 240.

In some embodiments, such as those that use the source light photo sensor 215, electromagnetic glass 225 can be located between the source light photo sensor 215 and the diamond assembly 240. In some embodiments, the diamond assembly 240 can emit electromagnetic interference (EMI) signals. In some instances, the source light photo sensor 215 can be sensitive to EMI signals. That is, in such instances, the source light photo sensor 215 performs better when there is less EMI affecting the source light photo sensor 215. The electromagnetic glass 225 can allow light to pass through the electromagnetic glass 225, but inhibit transmission of electromagnetic signals. Any suitable electromagnetic glass 225 can be used. In alternative embodiments, any suitable EMI attenuator can be used.

The concentrator 230 can be configured to concentrate light from the mirror tube assembly 220 (and/or the electromagnetic glass 225) into a more narrow beam of light. The concentrator 230 can be any suitable shape, such as parabolic. The diamond assembly 240 can include a diamond with one or more NV centers. The concentrator 230 can concentrate light from the LED 205 into a beam of light with a cross-sectional area that is similar to the cross-sectional area of the diamond. That is, the light from the LED 205 can be concentrated to most effectively flood the diamond with the light such that as much of the light as possible from the LED 205 passes through the diamond and/or such that as many NV centers as possible are excited by the light. The concentrator 230 may include a ring mount that is configured to hold the concentrator 230 at a secure location within the housing 210.

The diamond assembly 240 can include any suitable components. For example, as mentioned above, the diamond assembly 240 can include a diamond. The diamond can be located at the center of the diamond assembly 240. The diamond assembly 240 may also include one or more circuit boards that are configured to modulate electromagnetic signals applied to the diamond. In an illustrative embodiment, the diamond assembly 240 includes a Helmholtz coil 241 (see FIG. 7). For example, a three-dimensional Helmholtz coil 241 can be used counteract or cancel unwanted magnetic fields from affecting the diamond. In an illustrative embodiment, the circuit boards or other electronics can emit EMI signals. In some embodiments, the diamond assembly 240 includes a red filter that allows red light emitted from the diamond to pass through to the modulated photo sensor 250. In alternative embodiments, the red filter can be located at any suitable location between the diamond and the modulated photo sensor 250. In yet other embodiments, the red filter may not be used.

In some embodiments, the retaining rings 235 can be used to hold one or more of the elements of the magnetometer 200 within the housing 210. Although FIG. 2 illustrates two retaining rings 235, any suitable number of retaining rings 235 may be used. In some embodiments, the retaining rings 235 may not be used.

Similar to the concentrator 230, the concentrator 245 is configured to concentrate light emitted from the diamond assembly 240 into a more narrow beam. For example, the concentrator 230 can be configured to concentrate light into a beam that has the same or a similar cross-sectional area as the modulated photo sensor 250. The concentrator 245 can be configured to focus as much light as possible from the diamond assembly 240 to the modulated photo sensor 250. By increasing the amount of light emitted from the diamond assembly 240 that is sensed by the modulated photo sensor 250, the sensitivity of the magnetometer 200 can be increased.

As mentioned above, electromagnetic glass 225 can be located between the diamond assembly 240 and the modulated photo sensor 250 to shield the modulated photo sensor 250 from EMI signals emitted from the diamond assembly 240. The sensor plate 255 can be used to hold the modulated photo sensor 250 in place such that the modulated photo sensor 250 receives the concentrated light beam from the concentrator 245 (and/or the diamond assembly 240). A lens tube coupler 260 may be used as an end cap to the housing 210, thereby holding the various elements in place inside the housing 210.

FIG. 3 is a block diagram of a computing device in accordance with an illustrative embodiment. An illustrative computing device 300 includes a memory 310, a processor 305, a transceiver 315, a user interface 320, a power source 325, and an magnetometer 330. In alternative embodiments, additional, fewer, and/or different elements may be used. The computing device 300 can be any suitable device described herein. For example, the computing device 300 can be a desktop computer, a laptop computer, a smartphone, a specialized computing device, etc. The computing device 300 can be used to implement one or more of the methods described herein.

In an illustrative embodiment, the memory 310 is an electronic holding place or storage for information so that the information can be accessed by the processor 305. The memory 310 can include, but is not limited to, any type of random access memory (RAM), any type of read only memory (ROM), any type of flash memory, etc. such as magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., compact disk (CD), digital versatile disk (DVD), etc.), smart cards, flash memory devices, etc. The computing device 300 may have one or more computer-readable media that use the same or a different memory media technology. The computing device 300 may have one or more drives that support the loading of a memory medium such as a CD, a DVD, a flash memory card, etc.

In an illustrative embodiment, the processor 305 executes instructions. The instructions may be carried out by a special purpose computer, logic circuits, or hardware circuits. The processor 305 may be implemented in hardware, firmware, software, or any combination thereof. The term “execution” is, for example, the process of running an application or the carrying out of the operation called for by an instruction. The instructions may be written using one or more programming language, scripting language, assembly language, etc. The processor 305 executes an instruction, meaning that it performs the operations called for by that instruction. The processor 305 operably couples with the user interface 320, the transceiver 315, the memory 310, etc. to receive, to send, and to process information and to control the operations of the computing device 300. The processor 305 may retrieve a set of instructions from a permanent memory device such as a ROM device and copy the instructions in an executable form to a temporary memory device that is generally some form of RAM. An illustrative computing device 300 may include a plurality of processors that use the same or a different processing technology. In an illustrative embodiment, the instructions may be stored in memory 310. The processor 305 may be powered by a battery such as the battery 500 (see FIG. 6).

In an illustrative embodiment, the transceiver 315 is configured to receive and/or transmit information. In some embodiments, the transceiver 315 communicates information via a wired connection, such as an Ethernet connection, one or more twisted pair wires, coaxial cables, fiber optic cables, etc. In some embodiments, the transceiver 315 communicates information via a wireless connection using microwaves, infrared waves, radio waves, spread spectrum technologies, satellites, etc. The transceiver 315 can be configured to communicate with another device using cellular networks, local area networks, wide area networks, the Internet, etc. In some embodiments, one or more of the elements of the computing device 300 communicate via wired or wireless communications. In some embodiments, the transceiver 315 provides an interface for presenting information from the computing device 300 to external systems, users, or memory. For example, the transceiver 315 may include an interface to a display, a printer, a speaker, etc. In an illustrative embodiment, the transceiver 315 may also include alarm/indicator lights, a network interface, a disk drive, a computer memory device, etc. In an illustrative embodiment, the transceiver 315 can receive information from external systems, users, memory, etc.

In an illustrative embodiment, the user interface 320 is configured to receive and/or provide information from/to a user. The user interface 320 can be any suitable user interface. The user interface 320 can be an interface for receiving user input and/or machine instructions for entry into the computing device 300. The user interface 320 may use various input technologies including, but not limited to, a keyboard, a stylus and/or touch screen, a mouse, a track ball, a keypad, a microphone, voice recognition, motion recognition, disk drives, remote controllers, input ports, one or more buttons, dials, joysticks, etc. to allow an external source, such as a user, to enter information into the computing device 300. The user interface 320 can be used to navigate menus, adjust options, adjust settings, adjust display, etc.

The user interface 320 can be configured to provide an interface for presenting information from the computing device 300 to external systems, users, memory, etc. For example, the user interface 320 can include an interface for a display, a printer, a speaker, alarm/indicator lights, a network interface, a disk drive, a computer memory device, etc. The user interface 320 can include a color display, a cathode-ray tube (CRT), a liquid crystal display (LCD), a plasma display, an organic light-emitting diode (OLED) display, etc.

In an illustrative embodiment, the power source 325 is configured to provide electrical power to one or more elements of the computing device 300. In some embodiments, the power source 325 includes an alternating power source, such as available line voltage (e.g., 120 Volts alternating current at 60 Hertz in the United States). The power source 325 can include one or more transformers, rectifiers, etc. to convert electrical power into power useable by the one or more elements of the computing device 300, such as 1.5 Volts, 8 Volts, 12 Volts, 24 Volts, etc. The power source 325 can include one or more batteries.

In an illustrative embodiment, the computing device 300 includes a magnetometer 330. In some embodiments, magnetometer 330 is an independent device and is not integrated into the computing device 300. The magnetometer 330 can be configured to measure magnetic fields. For example, the magnetometer 330 can be the magnetometer 100, the magnetometer 200, or any suitable magnetometer. The magnetometer 330 can communicate with one or more of the other components of the computing device 300 such as the processor 305, the memory 310, etc. For example, one or more photo detectors of the magnetometer 330 can transmit a signal to the processor 305 indicating an amount of light detected by the respective photo detector. The signal can be used to determine the strength and/or direction of the magnetic field applied to the diamond of the magnetometer 330. In alternative embodiments, any suitable component of the magnetometer 330 can transmit a signal to other components of the 300 (e.g., the processor 305), such as a Helmholtz coil, a source light photo detector, one or more modulated light photo detectors, a light source, etc.

FIG. 4 is a flow diagram of a method for detecting a magnetic field in accordance with an illustrative embodiment. In alternative embodiments, additional, fewer, and/or different operations may be performed. Also, the use of a flow diagram and arrows is not meant to be limiting with respect to the order or flow of operations. For example, in some embodiments, one or more of the operations may be performed simultaneously.

In an operation 405, power is provided to a light emitting diode (LED). Any suitable amount of power can be provided. For example, a 5 milli-Watt (mW) LED can be used. The LED can be powered by two or more AA batteries. In alternative embodiments, the LED can use more or less power. In some embodiments, the amount of power provided to the LED is modulated based on a particular application. In some embodiments, the operation 205 includes providing pulsed power to the LED to cause the LED to alternately lighten and darken. In such embodiments, any suitable frequency and/or pattern can be used. In alternative embodiments, the operation 405 can include causing any suitable device to emit non-polarized light.

In an operation 410, light emitted from the LED is sensed. Sensing the light from the LED can include using a photo detector. The operation 410 can include determining an amount of green light emitted from the LED. In some embodiments, the operation 410 is not performed.

In an operation 415, light from the LED is focused into a diamond. The diamond can include one or more NV centers. The light can be focused as to excite as many of the NV centers as possible with the light from the LED. Any suitable focusing method can be used. For example, lenses or light pipes can be used to focus light from the LED to the diamond.

In an operation 420, light from the diamond is focused to a photo detector. Light from the LED passes through the diamond, is modulated by the diamond, and is emitted from the diamond. The light emitted from the diamond is focused to a detector such that as much light emitted from the diamond as possible is detected by the photo detector. In an operation 425, the light from the diamond is sensed by the photo detector. In an illustrative embodiment, the operation 425 includes determining the amount of red light emitted from the diamond.

In an operation 430, a magnetic field applied to the diamond is determined. In embodiments in which operation 410 is performed, the amount of red light emitted by the diamond is compared to the amount of green light emitted from the LED to determine the magnetic field. In embodiments, in which operation 410 is not performed, the amount of red light emitted from the diamond is compared to a baseline quantity of red light. In alternative embodiments, any suitable method of determining the magnetic field applied to the diamond can be used.

In an illustrative embodiment, noise in the light emitted from the LED can be compensated for. In such an embodiment, noise in the light emitted from the LED can be detected by a photo detector, such as the photo detector used for the operation 410. Noise in the light emitted from the LED passes through the diamond and is sensed by the photo detector that senses light emitted from the diamond, such as the photo detector used for the operation 425. In an illustrative embodiment, amount of light detected in the operation 410 is subtracted from the light detected in the operation 430. The result of the subtraction is the changes in the light caused by the diamond.

In an illustrative embodiment, any of the operations described herein can be implemented at least in part as computer-readable instructions stored on a computer-readable memory. Upon execution of the computer-readable instructions by a processor, the computer-readable instructions can cause a node to perform the operations.

The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being “operably couplable,” to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” Further, unless otherwise noted, the use of the words “approximate,” “about,” “around,” “substantially,” etc., mean plus or minus ten percent.

The foregoing description of illustrative embodiments has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents. 

What is claimed is:
 1. A device comprising: a diamond assembly including a diamond with one or more nitrogen vacancies; a light emitting diode configured to emit light toward the diamond; a first photo sensor configured to sense a first portion of the light emitted by the light emitting diode, wherein the first portion of the light does not travel through the diamond; a second photo sensor configured to sense a second portion of the light emitted by the light emitting diode, wherein the second portion of the light travels through the diamond; and a processor operatively coupled to the first photo sensor and a second photo sensor, wherein the processor is configured to: compare a first signal received from the first photo sensor with a second signal received from the second photo sensor; and determine, based on the comparison of the first signal and the second signal, a strength of a magnetic field applied to the diamond.
 2. The device of claim 1, further comprising a first filter between the light emitting diode and the first photo sensor, wherein light traveling through the first filter and to the first photo sensor is substantially green.
 3. The device of claim 1, further comprising a second filter between the diamond and the second photo sensor, wherein light traveling through the second filter and to the second photo sensor is substantially red.
 4. The device of claim 1, further comprising a heat sink configured to dissipate heat created by the light emitting diode.
 5. The device of claim 1, further comprising a battery configured to provide power to the light emitting diode and the processor.
 6. The device of claim 1, further comprising a sensor plate, wherein the second photo sensor is disposed on the sensor plate.
 7. The device of claim 1, wherein the light emitted from the light emitting diode is substantially green.
 8. The device of claim 1, further comprising: a first electromagnetic glass positioned between the first photo sensor and the diamond assembly, wherein the first electromagnetic glass is configured to shield the first photo sensor from first electromagnetic interference emitted by the diamond assembly; and a second electromagnetic glass positioned between the diamond assembly and the second photo sensor, wherein the second electromagnetic glass is configured to shield the second photo sensor from second electromagnetic interference emitted by the diamond assembly.
 9. The device of claim 1, wherein the first photo sensor is configured to detect noise in the light emitted from the light emitting diode, and wherein the processor is further configured to compensate for noise in the second portion of the light based on the detected noise in the light emitted from the light emitting diode.
 10. The device of claim 1, further comprising a three-dimensional Helmholtz coil surrounding the diamond.
 11. A method comprising: emitting light from a light emitting diode; sensing, at a first sensor, a first light portion, the first light portion being a portion of the light emitted by the light emitting diode that has not traveled through a diamond with a nitrogen vacancy; sensing, at a second sensor, a second light portion, the second light portion being a portion of the light emitted by the light emitting diode that has traveled through the diamond with the nitrogen vacancy; and comparing the first light portion to the second light portion to determine a strength of a magnetic field applied to the diamond.
 12. The method of claim 11, wherein said comparing the first light portion to the second light portion comprises comparing a strength of the first light portion to a strength of the second light portion.
 13. The method of claim 11, wherein a frequency of the first light portion is a green color, and wherein a frequency of the second light portion is a red color. 